For most of us, walking is an unremarkable affair. A basic human function that barely registers in everyday consciousness.

There are people who choose to walk for the sake of walking, true, but we can ignore them and their unique, admirable approach to existence.

By and large, walking falls into that category of activity we take for granted, alongside other such quality physical experiences as drinking water and going to the toilet. They don’t tend to require much thought, time and effort, which is why they can wreak havoc on a schedule of back-to-back meetings.

Every now and then we find ourselves walking to the post box, the convenience store or a neighbour’s house. Typically, the most challenging part is putting our shoes on before we leave home.

The soft and subtle sounds that herald something satisfying? Text message notifications? A match being lit? A can of drink being opened?

Or the loud, intrusive and abrasive sounds that alert us to something awful? The piercing shriek of an ambulance siren? Your car’s graunching complaints when you fumble a gear change? The shrill whistle of a descending missile? The cruel insistence of your alarm clock?

The sounds that really get our attention are those that warn us something is wrong. An evolutionary legacy. We must either run toward – to save others – or away – to save ourselves.